ResonantLive Sound Archive

Equipment file · Loudspeaker driver

Permanent-magnet dynamic driver

Jensen · 1930

Evidence status · documented

Identity and core specifications are documented; some historical fields remain unavailable.

In 1930 Jensen introduced what it describes as the first permanent-magnet dynamic loudspeaker, replacing the electromagnet field coil of earlier dynamic speakers with a built-in permanent magnet. This removed the need for a separate field supply, simplifying installation in radios and sound equipment.

Introduced
1930
Category
Loudspeaker driver
Intended use
Radio, public address and commercial loudspeakers
Production
Jensen Radio Manufacturing Company, Chicago

Equipment photographs · 1

Jensen ad for Alnico 5 speakers

1 / 1 · Jensen ad for Alnico 5 speakers

Jensen ad for Alnico 5 speakers·Jensen Radio Manufacturing Co. (1945 advertisement)·Public domain

Why it mattered

  1. 01

    Dropping the field-coil supply made dynamic loudspeakers smaller, cheaper and easier to deploy away from a wired studio or theatre, which mattered for portable PA.

  2. 02

    It continued the moving-coil line Peter Jensen began with the [[magnavox-telemegafone|Magnavox Telemegafone]].

Engineering record

Introduction
First permanent-magnet dynamic loudspeaker, introduced by Jensen in 1930[1]

Original pricing

No reliable period price located

2026 equivalent

Not calculated without a reliable original price.

Public price evidence was not sufficient to publish a defensible original figure.

Use in the field

No named deployment could be tied to this exact item by a checked source yet. Know of one? Suggest it on the contribute page.

Manuals & original documents

No authoritative manual or original document has been located for this profile.

Sources

  1. 1History of Jensen LoudspeakersJensen Loudspeakers · reference

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